Nowadays, people spend much time sitting during working hours and free time. The amount of exercising is often quite small. For this other reasons, painful conditions and disorders of the musculoskeletal system are very common.
Some people work out actively and take different forms of exercise. Going to gyms and using the gym devices is one way to stress one's body and muscles. The problem often is that a person does not have enough time to work out, or going outdoors or to work out is experienced to be difficult. There exist workout instruments for use at homes, but such instruments are not widely used.
Publications U.S. Pat. No. 6,159,133 A and DE 10 2006 013 366 A1 disclose a chair with a workout mechanism integrated under the chair or to the back of the chair. These mechanisms are complex and take up a great deal of space and must be taken into account already in designing and making the chair.